Systems and methods for monitoring well conditions during drilling operations

ABSTRACT

Disclosed are systems and methods for monitoring real-time conditions in a well during drilling of the well. The process includes receiving technical parameters in real-time as input to a processor adapted for employing the technical parameters in calculating kick tolerance and/or kick intensity of the well. The processor calculates kick tolerance and/or kick intensity of the well using the technical parameters as well as static values. The kick tolerance and/or kick intensity are displayed to a user in a user interface connected to the processor. The processor further determines when a predetermined alarm set point for at least one of the kick tolerance and/or kick intensity is achieved, corresponding to a condition requiring remedial action. The system enables the user to take the required remedial action to influence well operations or update the value of at least one technical parameter employed in calculating kick tolerance and/or kick intensity.

FIELD OF THE INVENTION

The field of the invention is oil and gas well drilling, and more particularly real-time monitoring of parameters during oil and gas drilling operations.

BACKGROUND

In the conduct of oil and gas drilling operations, it is important to maintain pressure control of an oil and gas well. One primary means of accomplishing well control during drilling is by adjusting and maintaining the density of the drilling fluid column extending from the drilling rig or drilling vessel downwards around the drill string to the drill bit near the bottom of the wellbore. Drilling fluid is also referred to as drilling mud. The density of this drilling fluid column combined with its height, which may extend as much as 25,000 feet or more, exerts a very large hydrostatic pressure upon the subterranean formation. When the hydrostatic pressure of the drilling fluid column exceeds the pore pressure of the formation, the oil and gas reservoir fluids in the subterranean formation are controlled from release into the wellbore by the pressure overbalance. Thus, drilling fluid density is one manner of controlling the pressure applied to the subterranean formation during drilling.

A release of formation fluid (or gas) from a subterranean formation into a well bore during drilling, resulting from formation fluid pressure exceeding the drilling fluid pressure, is called a “kick.” It is common practice to plan for and attempt to understand the propensity of a subterranean formation to generate such a kick into the well during drilling. The volume of a kick the wellbore is able to tolerate before the formation breaks down is referred to as the “kick tolerance.” The pressure corresponding to this tolerable volume is referred to as the “kick intensity.” The kick tolerance of the well and the kick intensity are values that may be calculated during the well planning stages. The propensity of a well to generate a kick is monitored both before and during drilling.

Well planning before drilling a well includes the process of evaluating and calculating important values that are likely to be observed during the drilling of a well. Kick tolerance and kick intensity values typically are calculated manually prior to drilling a well. However, parameters that are important in calculating kick tolerance or kick intensity sometimes change during drilling. In the past, data generated during drilling has been used to manually update calculations of kick tolerance and kick intensity periodically during the drilling process.

Human error is possible whenever human operators engage in a technical process. If calculations are not manually updated, or are not manually updated in a timely manner, then the values used by a drilling engineer and/or field personnel for kick tolerance and kick intensity may not be accurate at a given point in time during drilling. If kick tolerance and/or kick intensity are not accurately represented, updated or understood in real-time, the risk of an undesirable well control event, i.e., a well control event more serious than a kick, is increased.

The invention provides improved methods and systems for measuring, calculating and monitoring important parameters of a well during drilling of the well in order to ensure safe drilling of the well. Such parameters include kick tolerance and kick intensity.

BRIEF DESCRIPTION OF THE FIGURES

These and other objects, features and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying drawings where:

FIG. 1 is a schematic diagram illustrating the relationship between system components according to one embodiment.

FIG. 2 is a flowchart illustrating overall method steps according to one embodiment.

FIG. 3 is an example of a display in a format adapted for alerting personnel when kick tolerance and/or kick intensity changes according to one embodiment.

SUMMARY

According to one aspect, a process is provided for monitoring conditions in a well during drilling of the well in which technical parameters relevant to the conduct of well drilling operations are generated. The process includes receiving the technical parameters in real-time as input to a processor adapted for employing the technical parameters in calculating kick tolerance and/or kick intensity of the well. The processor calculates kick tolerance and/or kick intensity of the well using the technical parameters. The kick tolerance and/or kick intensity are displayed to a user in a user interface connected to the processor. The processor further determines when a predetermined alarm set point for at least one of the kick tolerance and/or kick intensity is achieved. The predetermined alarm set point corresponds to a condition requiring remedial action. The processor further notifies a user of achievement of the predetermined alarm set point, thereby enabling the user to take the required remedial action to influence well operations or update the value of at least one technical parameter employed in calculating kick tolerance and/or kick intensity.

According to another aspect, a system is provided for monitoring conditions in a well during drilling of the well in which technical parameters relevant to the conduct of well drilling operations are generated. The system includes a computer processor in communication with a source of technical parameters relevant to the conduct of a well drilling operation, wherein the computer processor is configured to execute computer readable instructions to:

-   -   receive the technical parameters in real-time;     -   calculate kick tolerance and/or kick intensity of the well using         the technical parameters;     -   communicate signals representing the kick tolerance and/or kick         intensity to a user interface connected to the processor;     -   determine when a predetermined alarm set point for at least one         of the kick tolerance and/or kick intensity is achieved, wherein         the predetermined alarm set point corresponds to a condition         requiring remedial action; and     -   communicate signals when it is determined that the predetermined         alarm set point is achieved.

The system further includes a user interface connected to the processor capable of displaying the kick tolerance and/or kick intensity calculated by the processor and/or alerting a user when it is determined that the predetermined alarm set point is achieved.

DETAILED DESCRIPTION

A system 100 for monitoring real-time data also referred to herein as parameters and technical parameters according to one embodiment is illustrated in FIG. 1. The system 100 includes a computer processor 102 in communication with a source of dynamic real-time data 104, wherein the data are relevant to the performance of a well which is being drilled. The computer processor 102 can also be in communication with a user input device 106 and a visual display 108. The computer processor 102 obtains a plurality of real-time values from the source of dynamic real-time data 104. In one embodiment, the source of dynamic real-time data 104 is a plurality of field instruments or sensors 105 for gathering real-time data from a well during drilling. In one embodiment, the source of dynamic real-time data 104 is a process control system connected to sensors 105 to monitor a well drilling process. The process control system can be, for instance, a distributed control system, a programmable logic controller, a remote terminal unit or a supervisory control and data acquisition unit. In one embodiment, the source of dynamic real-time data 104 is a database which is updated periodically in real-time, e.g., on a frequency of between five times per second and once every 30 seconds. A non-transitory processor readable medium containing computer readable software instructions used for displaying dynamic real-time data can be read by the processor 102. The computer processor 102 can include any suitable computer processor, such as at least one microprocessor containing at least one integrated circuit, for carrying out various functions according to the software instructions as would be apparent to one skilled in the art. The software instructions can be provided in a program in any programming language readable and executable by the processor 102. The user input device 106 can be any convenient means by which a user can provide input to the computer processor 102, including, for example, a cursor, a keyboard, a touchscreen monitor or a microphone. The visual display 108 can be any user interface including a visual display such as a computer monitor or a personal digital assistant (PDA) screen. The display can be capable of displaying a profile including at least one limit line representing an alarm limit, a deviation limit or a minimum or maximum limit. In one embodiment, the computer processor 102 effectively compares each of the plurality of real-time values to a predetermined normal range and a user-defined limit selected from an upper alarm limit, a lower alarm limit, an upper deviation limit, a lower deviation limit, a maximum value and a minimum value. In some cases, the normal range can be a single normal value, wherein the lower end of the range is the same as the upper end of the range. The computer processor 102 generates signals which are communicated to the visual display 108 to generate a graphical display. The graphical display can be made up of any of a variety of known graphical methods for displaying data. The visual display 108 can optionally include auditory capabilities so that audible alarms can be generated.

FIG. 2 is a flowchart illustrating a method 200 according to one embodiment. The steps of the method 200 are carried out by the processor 102 in accordance with the software instructions. In step 202, a signal indicative of a plurality of real-time values is processed. In step 204, the plurality of real-time values is used in calculations of calculated values to be monitored. The calculated values include numeric values of interest as well as calculated alarm values as described further herein below. In step 206, a signal for communication with a user interface is generated to produce a display of the calculated values, e.g., on a visual display. The real-time values are technical parameters relevant to the performance of drilling a well. Examples of real-time values include, but are not limited to, mud density in, bit depth, hole depth, cement unit pump combined rate, mud weight out, and combinations thereof. The real-time values can be process parameters obtained from a process control system which includes field instruments or sensors 105 for measuring process parameters. In one embodiment, the real-time values can be stored as data in a table or database that is updated to reflect real-time values periodically. The table can be updated to reflect real-time values every user-defined increment of time. For example, the database can be updated every user-defined number of seconds or minutes. Alternatively, the database can be updated to reflect real-time values when the processor 102 automatically detects a signal indicating a change in one or more of the real-time values.

At a drilling rig site, real-time data in the form of drilling variables or technical parameters are collected and aggregated. In some instances, there may be real-time data feeds of drilling variables available to a drilling engineer. The term “drilling engineer” is used to include field personnel, engineers and operators that may have need to monitor important parameters related to a well during drilling of the well, particularly kick tolerance and/or kick intensity. In some instances, real-time data feeds may be unavailable, and such values may need to be employed as a static value. In the practice of the invention, software is employed to automatically calculate kick tolerance and kick intensity using the real-time data and the static values, and display them for the drilling engineer to review and monitor during the drilling of a well. The displayed calculated kick tolerance and kick intensity are updated in real-time. The processor receives the real-time data at a frequency of, for example, five data points per second. The processor then calculates kick tolerance and kick intensity using the real-time data values as well as static values that are manually input into the software.

Kick tolerance is the maximum volume of a gas kick (measured in barrels) that still allows for successful shut-in of the well in and circulation of the kick “out of hole,” without breaking down the formation strength at the casing shoe depth or overcoming the weakest anticipated fracture pressure in the wellbore. In order to calculate kick tolerance, assumed are kick intensity (in pounds per gallon or ppg) and the depth in the well that the kick will occur. Kick intensity may be described as the difference between the maximum anticipated formation pressure and the planned mud weight used in the wellbore. Drilling engineers normally calculate kick intensity at total depth (“TD”) for each of the well's hole sections.

There are several factors that may impact kick tolerance. The leak off test of the casing shoe may be important. The greater the leak off test, i.e., the greater the pressure required to cause the last casing shoe or formation to fracture, the greater the kick tolerance will be, and the deeper the total depth that can be drilled. The larger the total vertical depth of the well, the less the kick tolerance will be for a given situation. The heavier the mud weight, the greater the kick tolerance will be in a wellbore for a given situation (other factors being equal). On the other hand, the higher the formation pressure, the higher the kick intensity will be for a given well. Higher kick intensity leads to reduced kick tolerance. The size of the expected kick is important as well, in part because the larger the expected kick, the greater the required kick tolerance during drilling. It is important to update kick tolerance values during drilling operations because the input parameters are likely to change during drilling. In the practice of the invention, software may be used to provide logic alarms that will alert the user when, during the course of drilling operations, there is a change in the kick tolerance of the well. Thus, providing alarms on the kick tolerance values and static variables that need updating may be involved in the process of the invention.

The value of parameters that may be important in the calculations and alarming of kick tolerance and kick intensity include, for example: mud weight in, bit depth, hole depth, cement unit pump data, mud weight out, leak off test value of the deepest run casing, total vertical depth of the casing shoe of the deepest run casing, total vertical depth of the current hole section, and maximum pore pressure, among others.

Exemplary coding for real-time calculations and alarm logic performed by the processor is described as follows. Table 1 lists the static values (constants) and the real-time values used for the calculations. The real-time values used for the calculations are received by the processor as data streams. Table 2 lists the formulas used by the processor to calculate the values, i.e., the outputs that may be displayed or otherwise reported to the user. The formulas include variables as described in Table 1. The outputs are also described in Table 2. The designations used are completely arbitrary.

TABLE 1 Formula Symbol Unit Description Static Value Parameters: LOT ppg leak off test value; PIT of previous casing string TVDShoe ft total vertical depth (TVD) of previous casing string TD ft total depth (TD) of hole section MaxPP ppg “Worst Case” pore pressure (PP) AnnBHAVol bbl/ft Annuls by bottom hole assembly (BHA) Volume Factor BHALength ft BHA Length Real-time Value Parameters: MDIA lbm/galUS Mud Density In BITDEP ft Measured Depth of the bit CFROA bbls/ft Cement pumps - combined rate HLDepth ft Hole depth MWOut ppg Mud weight out - Coriolis meter

TABLE 2 Variable Formula Description KTMISICP (LOT-MDIA)*0.052*TVDShoe maximum allowable shut-in casing pressure KTKickIntensity MaxPP-MDIA kick intensity KTOL (KTMISICP- kick tolerance (KTKickIntensity*0.052 *HLDepth))/(MDIA*0.052-0.1) *AnnBHAVolfactor KTKIConsrv MaxPP-MWOut conservative value for kick intensity KTMISICPConsrv (LOT-MWOut)*0.052*TVDShoe conservative value for maximum allowable shut-in casing pressure KT Consrv (KTMISICPConsrv- conservative value for kick (KTKIConsrv*0.052*HLDepth)) tolerance /(MWOut*0.052-0.1) *AnnBHAVolfactor KT IF(KTOL/AnnBHAvolfactor calculated value to trigger an BHALengthalarm >BHALength,1,0) alarm alerting the user to update the BHA Length (i.e., manually update the value input into the system) KTBHAalarm IF(BITDEP<TVDShoe,1,0) calculated value to trigger an alarm alerting the user to update the value for AnnBHAVol KTTVDShoealarm IF(CFROA>1,1,0) calculated value to trigger an alarm alerting the user to update the value for TVDShoe KT Update Alarm IF(OR(KTBHAalarm=1, calculated value to trigger an KTTDalarm=1, alarm alerting the user to take KTTVDShoealarm=1),1,0) note of the above mentioned alarms on static parameters KT MWPPalarm IF(MDIA>MaxPP,1,0) calculated value to trigger an alarm alerting the user to update the value for maximum pore pressure (MaxPP) used to calculate kick intensity

The application of the invention may further provide alarms and automatic updates to additional values as would be apparent to one skilled in the art.

The methods and systems disclosed herein may be utilized either at the drill site or remotely at data support centers, where the real-time kick tolerance values may provide early warning to drilling rig personnel when they should direct their attention to the task of identifying kicks. As a result, personnel are alerted in time to take remedial action and more serious well control events may be avoided.

Parameter values are raw data that may be collected in real-time by sensors associated with a well during drilling and aggregated. Then, such parameter values may be provided as data streams to software for processing and calculation of the kick tolerance and kick intensity. WellLink RT® is a software program commercially distributed by Baker Hughes, Inc of Houston, Tex. that may be employed in such a process. Discovery Web is likewise a software program commercially distributed by Kongsberg Oil & Gas Technologies AS (Norway) that may be employed in such a process. The gathered input data may be provided into industry algorithms for calculating kick intensity and kick tolerance, as illustrated in Table 2.

Alarms may be set by a user in the software program for many different conditions of interest, including, for example: (1) when kick tolerance has changed from a previously determined value (e.g., in a high/low or on/off (1/0) alarm system used for alerting personnel that the kick tolerance values have changed); and (2) when an update is needed to the annulus by bottom hole assembly (BHA) volume factor used in the calculations. The annulus by BHA volume factor can be updated by monitoring the bit depth in comparison to the depth of the casing shoe used in the kick tolerance formula. If the bit depth is above the total vertical depth of the casing shoe, there is a possibility that the rig may be tripping out of the hole and the rig personnel may be preparing to drill with a new BHA or engaging a new hole size. In such instances, the annulus by BHA volume factor should be updated in the calculation.

When continuing drilling operations require the setting of a casing string, it may become necessary to update the casing shoe depth and leak off test value (LOT) employed in the calculations. In this scenario, an alarm could be triggered by the presence of cement unit pressure. The logic in this scenario is that if the cement unit has pressure and/or is pumping, then it is most likely that a cementing operation is underway to cement a casing string or perform a leak off test. In both of these scenarios, new or updated data inputs would be needed for the casing shoe depth and leak off test in the kick tolerance calculations. These are operations that require updates to the formula inputs.

In another scenario, the kick tolerance may be larger than the volume between the hole and the BHA. It is possible to use an inequality to check for this condition. Should the kick tolerance be larger than the hole volume around the BHA, then additional attention is required by personnel to calculate the actual kick tolerance.

FIG. 3 shows an exemplary real-time visual display showing the calculations and alarms in a format that may alert personnel when kick tolerance changes. In the left portion of the figure, a graphical log is displayed of the real-time calculated values so that the user can easily monitor the current values and any changes. In the right portion of the figure, alarm values are shown. This alarm section utilizes numeric data displays in combination with the alarming capabilities to communicate text instructions to the user. When a condition exists to trigger an alarm from the logic in Table 3, the corresponding area in the display in FIG. 3 will highlight to alert the user.

Inputs to the formulas and the outputs on a visual display for use at a rig site or real-time data collection center may inform personnel of the kick tolerance based upon the well's current condition as measured by real-time sensors. The display may include an alarm section for alerts and a static input section to display values used in the calculations. When an alarm is triggered, the user interface can include values lighting up, flashing in color, auditory alarms and the like to get the user's attention.

A process for monitoring conditions in a well being drilled is disclosed. The process may comprise the steps of: (a) generating technical parameters relevant to the conduct of a well drilling operation; (b) supplying the technical parameters as input to a software program; (c) aggregating the technical parameters in the software program, the software program being adapted for employing the technical parameters in calculating kick tolerance or kick intensity of the well; (d) displaying the kick tolerance or kick intensity to a user; (e) providing a predetermined alarm set point for at least a first technical parameter, the alarm set point being established to correspond to a condition requiring remedial action; (f) determining when the alarm set point is achieved; and (g) notifying the user of achievement of the alarm set point, thereby enabling the user to take action whether the action is to influence the well operations or to update the value of at least one technical parameter employed in calculating kick tolerance and or kick intensity.

For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention. It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural references unless expressly and unequivocally limited to one referent.

Unless otherwise specified, the recitation of a genus of elements, materials or other components, from which an individual component or mixture of components can be selected, is intended to include all possible sub-generic combinations of the listed components and mixtures thereof. Also, “comprise,” “include” and its variants, are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that may also be useful in the materials, compositions, methods and systems of this invention.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. All citations referred herein are expressly incorporated herein by reference.

From the above description, those skilled in the art will perceive improvements, changes and modifications, which are intended to be covered by the appended claims. 

What is claimed is:
 1. A process for monitoring conditions in a well during drilling of the well in which technical parameters relevant to the conduct of well drilling operations are generated, the process comprising: (a) receiving the technical parameters in real-time as input to a processor adapted for employing the technical parameters in calculating kick tolerance and/or kick intensity of the well; (b) calculating kick tolerance and/or kick intensity of the well in the processor using the technical parameters; (c) displaying the kick tolerance and/or kick intensity to a user as calculated in the processor in a user interface connected to the processor; (d) determining when a predetermined alarm set point for at least one of the kick tolerance and/or kick intensity is achieved in the processor, wherein the predetermined alarm set point corresponds to a condition requiring remedial action; and (e) notifying a user of achievement of the predetermined alarm set point, thereby enabling the user to take the required remedial action to influence well operations or update the value of at least one technical parameter employed in calculating kick tolerance and/or kick intensity.
 2. The process of claim 1, wherein the technical parameters are selected from the group consisting of mud density in, bit depth, hole depth, cement unit pump combined rate, mud weight out, and combinations thereof.
 3. The process of claim 1, further comprising: receiving static values as input to the processor; and calculating kick tolerance and/or kick intensity of the well using a combination of the technical parameters and the static values; wherein the static values are selected from the group consisting of leak off test value, annulus by bottom hole assembly volume factor, bottom hole assembly length, total vertical depth of deepest run casing, total vertical depth of current hole section, maximum pore pressure and combinations thereof.
 4. The process of claim 1, wherein the kick tolerance and/or kick intensity is displayed to the user in the user interface at a real-time data support center remote from the well site.
 5. The process of claim 1, wherein the processor is in communication with a source of the technical parameters.
 6. The process of claim 5, wherein the source of the technical parameters is one or more sensors associated with the well during drilling.
 7. The process of claim 1, wherein the processor calculates kick tolerance and/or kick intensity on a frequency between once per 0.2 seconds and once per 30 seconds.
 8. A system for monitoring conditions in a well being drilled, the system comprising: (a) a computer processor in communication with a source of technical parameters relevant to the conduct of a well drilling operation, wherein the computer processor is configured to execute computer readable instructions to: i. receive the technical parameters in real-time; ii. calculate kick tolerance and/or kick intensity of the well using the technical parameters; iii. communicate signals representing the kick tolerance and/or kick intensity to a user interface connected to the processor; iv. determine when a predetermined alarm set point for at least one of the kick tolerance and/or kick intensity is achieved, wherein the predetermined alarm set point corresponds to a condition requiring remedial action; and v. communicate signals when it is determined that the predetermined alarm set point is achieved; and (b) the user interface connected to the processor wherein the user interface is capable of displaying the kick tolerance and/or kick intensity calculated by the processor and/or alerting a user when it is determined that the predetermined alarm set point is achieved.
 9. The system of claim 8, further comprising a user input device in communication with the processor.
 10. The system of claim 8, further comprising sensors associated with the well and in communication with the processor for collecting the technical parameters during drilling.
 11. The system of claim 8, wherein the technical parameters are received by the processor from a process control system selected from the group consisting of a distributed control system, a programmable logic controller, a remote terminal unit and a supervisory control and data acquisition unit. 